Apparatus for cooling hot metal strip or plate by laminar liquid flow



COCK 3,025,865

J. N. AD APPARATUS FOR COOLING HOT METAL STRIP OR PLATE BY LAMINAR LIQUID FLOW March 20, 1962 Filed Dec. 2, 1957 4 Sheets-Sheet 1 FIZZ Inventor 305 EPH NOEL' ADcocK Attorneys March-20, 1962 J. N. ADCOCK 3,025,865

APPARATUS FOR COOLING HOT METAL STRIP OR PLATE BY LAMINAR LIQUID FLOW Filed Dec. 2, 1957 4 Sheets-Sheet 2 Inventor DOSEPH NOEL ADCOCK A ttorneyg March 20, 1962 J. N. ADCOCK 3,025,865

APPARATUS FOR COOLING HOT METAL STRIP 0R PLATE BY LAMINAR LIQUID FLOW Filed Dec. 2, 1957 4 Sheets-Sheet 5 I (1231:)? .01. (10 f T-Mfg: w F/G.4

Inventor DOSEPH NOEL bgocK BWEW Attorneys March 20, 1962 J. N. ADcocK 3,025,865

APPARATUS FOR COOLING HOT METAL STRIP OR PLATE BY LAMINAR LIQUID FLOW Filed Dec. 2, 1957 4 Sheets-Sheet 4 Attorneys United States Patent 3 025,865 APPARATUS FOR CUULING HOT METAL STRIP 0R PLATE BY LAMINAR LIQUID FLOW Joseph Noel Adcock, Moorgate, Rotherham, England, as-

signor to The United Steel Companies Limited, Sheffield, England Filed Dec. 2, 1957, Ser. No. 700,011 9 Claims. (Cl. 134-422) This invention relates broadly to the cooling of hot metal strip or plate.

When steel is rolled into strip or plate it emerges hot from the rolling mills and is commonly cooled by water sprayed onto it. The water splashes on impinging onto the strip or plate.

It is possible to prevent the water from splashing, even though it may flow as jets from nozzles situated several feet above the strip. What is required is to make the jets assume parallel laminar form. By parallel laminar form we means a non-turbulent jet in which the molecules of the liquid are all moving substantially at the same velocity and in straight parallel lines with respect to each other. This kind of jet is characterised by its similarity in appearance to a clear glass rod, and on impingement upon a plane surface the liquid disperses along the surface without any substantial splash.

One object of my invention is to cool hot metal strip or plate without splash.

Another object of my invention is to provide an apparatus for producing a plurality of jets of liquid in parallel laminar form.

A further object of my invention is to provide improved cooling means in a rolling mill.

I have found that I can produce jets flowing in parallel laminar form by causing the liquid to flow to a nozzle through a sufficient length of smooth bore pipe to give direction and straightness to the stream, and by using a low operating head to ensure the absence of turbulence.

I have further found that the requirements are satisfied by discharging the liquid through syphon tubes, one to each jet.

One feature of this invention is the cooling of hot metal strip or plate by jets of water moving downwards from syphon tubes onto the strip or plate in parallel laminar flow.

Another feature of this invention is an apparatus for producing a number of jets of water or other liquid in parallel laminar form, this apparatus comprising a liquid container and a number of syphon tubes mounted in the container with their suction legs terminating a little distance above the bottom of the container, their discharge legs passing in liquid-tight fashion through the bottom of the container, and their tops lying below the top of the container, so that on filling the container all the syphon tubes will be flooded and simultaneous flow will begin through each. To ensure that the liquid flows satisfactorily in parallel laminar form the discharge leg of each syphon tube should have a straight length of at least 12 times its diameter, and I prefer to make this length 16 times the diameter.

Some apparatus according to the invention are shown in the drawings accompanying the provisional specification, in which FIGURE 1 is a longitudinal section through one apparatus;

FIGURE 2 is a longitudinal section through another apparatus;

FIGURE 3 is a transverse section on the line III-III in each of FIGURES 1 and 2;

FIGURE 4 is an enlarged view of the discharge end of one syphon tube.

In addition, in the accompanying drawing FIGURE 5 is a diagram of a rolling mill equipped with apparatus according to the invention.

In the apparatus shown in FIGURE 1 the liquid container is a metal box 3, and there are 20 syphon tubes 1 in it. The inlet ends of the syphon tubes alternate at the opposite sides of the box, as shown in FIGURE 3, and lie just so far above the bottom 2 of the box as to ensure that water can always enter them without obstruction.

The discharge ends of the tubes 1 are brazed in holes in the plate 2, which is recessed on its underside, as shown in FIGURE 4. The tubes 1 are maintained in a rigid vertical position by means of a stay plate 4. The tops or bends of the syphon pipes are maintained at an equal distance from the bottom plate 2.

Water is supplied through an inlet 5 of circular crosssection and a baffle plate 6 is interposed between the inlet 5 and the tubes 1 and is perforated to allow water to flow through it. The box is closed at the top, except for an air vent 7, and a sight glass 8 is incorporated in the side to indicate the water level.

In operation the water is turned on at a predetermined rate of flow and rises in the box 3 until the level in the box is higher than the top of the syphon bends. Thereupon the syphons establish themselves and the water level in the box rapidly falls until the discharge head, i.e. the depth of water in the box measured from the surface of the water to the discharge ends of the syphon tubes, is sufi'icient to give a total discharge through the syphons equal to the amount of water entering the box. This discharge is self-adjusting.

The entering water is free of entrained air, and turbulence is reduced by the bafile plate 6.

The box shown in FIGURE 1 is suitable for installation in a fixed position.

In a rolling mill, the hot strip or plate leaving the last mill stand travels horizontally along a roller rack. For cooling strip or plate by means of the invention, boxes are arranged in succession above the rack with their short sides parallel to the centre line of the rack and their long sides extending across it, each box being of such dimensions and containing so many syphon tubes as to project jets over the whole width of the strip or plate.

One such arrangement .is shown diagrammatically in FIGURE 5, the last mill stand being shown at 15 and the roller rack at 16, and the direction of movement of the strip being indicated by an arrow. The jets are indicated at 17.

Now strip travels at high speed and does not always lie flat. Sometimes, the leading end will raise itself into the air and sometimes a loop will form in the strip as it travels along. In either case, the leading edge of the strip or the crest of the loop could rise sufficiently to come into contact with the boxes. To prevent the boxes being damaged their bottoms are made of thick plates, and it is for the same reason that the plates forming the bottoms are recessed. In addition each plate 2 is secured in position by countersunk screws.

The boxes may advantageously be spaced somewhat apart from one another as shown in FIGURE 5. If each box had a bottom plate just equal to the width of the box there would be such a gap between adjacent boxes that the leading edge of the strip might become trapped in it. T o avoid this, the plates 2 may advantageously project out from each box to form flanges as shown in FIGURES 3 and 5, so that the plates of adjacent boxes almost touch one another. Further, the flange projecting towards the oncoming strip is slightly turned upwards,

as shown at 14, so as to present an inclined surface to the speaeee leading edge of the strip if this should strike the underside of the plate.

If each box must be easily moved out of its operating position, so as to give access to the roller rack or for any other reason, it may be mounted to swing, as shown in FIGURE 2. In this apparatus the water inlet is a closed trough 9 leading from an open-topped tundish 10'. The box is pivoted at 11 on a circular shaft holding several boxes. The boxes may be swivelled vertically either by rotation of the pivot shaft or by rotation of the box upon the shaft, and the box is maintained in a level working position by abutment upon a rigid structure at 12.

Water is introduced into each box by means of a pipe 13 which projects downwards into the tundish to give a submerged delivery, and the quantity of water flowing through the box is governed by a valve in a supply pipeline. Air entrained during the introduction of the water into the tundish is removed during the passage of the water along the trough 9, assisted by the action of the baffle plate 6.

I claim:

1. An apparatus for feeding cooling liquid comprising a container for liquid and means for producing a number of jets of liquid in parallel laminar form, comprising a plurality of parallel siphon tubes mounted in said container, the suction leg of each tube terminating at small distance above the bottom of said container, the discharge leg of each tube passing in liquid-tight fashion through the bottom of said container and the top of each tube lying below the top of the container, and means to feed Water to the container at a rate at least equal to the lowest rate of continuous discharge of said tubes determined by the lowest Water level in the container permitting continuous flow so as to maintain continuous discharge through all the tubes.

2. An apparatus as claimed in claim 1 in which the discharge leg of each syphon tube has a straight length of at least 16 times its diameter.

3. An apparatus as claimed in claim 1 in which the container has a liquid inlet in one wall and a perforated batlle plate is interposed between the inlet and the syphon tubes.

4. In a rolling mill having a plurality of mill stands, the combination of a roller rack for hot strip or plate leaving the last mill stand, and a plurality of apparatus arranged in succession above said rack to project jets of liquid over the whole width of strip or plate travelling along said rack, each of said apparatus comprising a container for liquid and means comprising a plurality of parallel syphon tubes each having a suction leg terminating in the container to discharge liquid from said container as jets moving downwards in parallel laminar flow.

5. A combination as claimed in claim 4 in which the containers are spaced apart from one another and their bottoms have flanges which substantially close the gaps between adjacent containers.

6. A combination as claimed in claim 5 in which on each container a flange projecting towards oncoming strip is turned upwards to present an inclined surface to the leading edge of the strip.

7. A combination as claimed in claim 4 in which the containers are mounted to rock about an axis parallel to the centre line of the roller rack so that they can be swung outof the operating position.

8. A combination as claimed in claim 7 in which each container is rigid with an open tundish to which cooling water is supplied and from which it enters the container.

9. A combination as claimed in claim 4 in which the syphon tubes in each apparatus are arranged in at least one line transverse to the longitudinal axis of the roller rack.

References Cited in the file of this patent UNITED STATES PATENTS 858,522 Low July 2, 1907 974,336 Alt Nov. 1, 1910 1,998,192 Haswell Apr. 16, 1935 2,536,208 Nystrom Jan. 2, 1951 2,628,924 Johnston Feb. 17, 1953 2,696,823 Scott Dec. 14, 1954 2,702,042 Smith Feb. 15, 1955 2,828,761 Weibert Apr. 1, 1958 

